1. Field of the Invention
The present invention relates to a hollow golf club head, and more particularly to a golf club head (hereinafter simply referred to as a head) of wood type or similar shape.
2. Description of the Related Art
As the wood type golf club head such as a driver or a fairway wood, hollow and metallic heads are commonly employed. Generally, a hollow golf club head 1 of wood type includes a face portion 2 for hitting a ball, a crown portion 3 configuring an upper face portion of the golf club head, a sole portion 4 configuring a bottom face portion of the golf club head, a side portion 5 configuring a side face portion on a toe side, a back side and a heel side of the golf club head and a hosel portion 6, as shown in FIG. 4. A shaft 7 is inserted into the hosel portion 6 of the golf club head and fixed by adhesives. Recently, many golf club heads called a utility club have appeared on a market. As one kind of this utility golf club head, various golf club heads similar to the wood type golf club head (i.e., having the face portion, sole portion, side portion, crown portion and hosel portion) are commercially available on the market.
This hollow golf club head is made of aluminum alloy, stainless or titanium alloy. In late years, titanium alloy is particularly employed.
Recently, the hollow golf club head partially made of fiber reinforced plastic is commercially available on the market.
In late years, the driver heads are increased in size, and those of 350 cc-over category and or 400 cc-over category have appeared on the market.
In this way, if the heads are increased in size, the distance between center of gravity of the head and the hosel portion is larger, and moment of inertia of the head is larger. Since such head with the large moment of inertia is less likely turned at a swing, the player, especially at a beginner's level, is easy to slice.
In FIG. 9 of JP-A-7-67991, a wood type golf club head having a high specific gravity material attached on an outer surface of a hosel portion on a heel side is shown.